The 49ers just built a new stadium. The Raiders want a new stadium. The A’s want a new stadium in San Jose. Oakland hopes the A’s will stay in their old stadium. Los Angeles wants the Raiders to build a stadium down south. The Earthquakes are building their own stadium in San Jose. The Giants’ stadium is paying for itself. The Warriors are trying to build a new home on the shores of San Francisco. The Sharks are outgrowing their tank. And let’s not forget the collegians. Private Stanford recently built itself a new stadium, in one short year. Public Cal took years to shake protesters out of trees and shake money out of its alumni to refurbish ol’ Memorial Stadium.

Put it all together and you have a nasty case of SFS. While fans struggle to pay for increasingly expensive tickets — along with their mortgages and health care bills and college tuition — billionaire owners spend years building monuments for their millionaire friends.

Don’t get me wrong. I’m happy for all the billionaires and millionaires. I just wish they’d leave us out of their business. Instead, a day barely goes by without another stadium-related headline, touting someone’s new castle or another threat to leave. Sports fans like sports. Not commercial real estate.

Why am I such a crank about stadiums? Let me count it up.

1. Stadiums should be privately funded. San Francisco stood up to the Giants 20 years ago and the result has been fabulous. Santa Clara capitulated for the 49ers and the long-term impact on that community could be devastating. Why should the public pay for someone’s office space?

2. Stadiums should last hundreds of years. The idea that these massive structures are disposable, with a lifespan less than 50 years, is a monument to American stupidity and waste. The great structures of Europe and Asia have stood for hundreds of years and still function. Why do we knock down our cathedrals after a few decades?

3. Stadiums should be inclusive, not exclusive. Especially if there is any public money involved. Every time a new stadium goes up, ticket prices soar. Throw in variable ticket pricing (i.e., gouging for popular games) and private seat licenses and it’s a one-percent fiesta. Whatever happened to the cheap seats?

Once the construction cranes disappear, Bay Area sports fans should be sitting pretty. If Oakland gets its act together — and that’s a very iffy if — every team in the Bay Area could have a new home within five years.

Which would bring us to the year 2019. AT&T Park would be nearly 20 years old. And Larry Baer can begin his campaign for a new stadium for the Giants.